Corn plant named morning star

ABSTRACT

A new and distinct corn plant, which is the product of a cross between gamagrass,  Tripsacum laxum,  and diploid perennial teosinte,  Zea diploperennis.  This plant is fertile, has proven to be cross compatible with  Zea mays  L. and offers an avenue to expand the gene pool for commercial corn varieties. The instant plant is perennial with well developed rhizomes, aerenchyma tissue in its roots, abundant seed and prolific vegetation production, traits that give it improved value as a forage crop.

BOTANICAL CLASSIFICATION

Zea diploperennis×Tripsacum laxum

CULTIVAR NAME

‘Venus Express’

BACKGROUND OF THE NEW PLANT

Two wild grasses, diploid perennial teosinte, Zea diploperennis Iltis,Doebley and Guzman, and gamagrass, Tripsacum laxum Nash, have beencrossed to produce a fully fertile bridge species that may improve corn,Zea mays L., by conferring beneficial traits such as pest resistance anddrought tolerance. Z diploperennis (hereafter referred to asdiploperennis), was an unknown wild relative of corn until it wasdiscovered, apparently on the threshold of extinction, in the mountainsof Jalisco, Mexico in the late 1970's. It is in the same genus as corn,has the same chromosome number as corn (n=10), and hybridizes easilywith it. Gamagrass is a more distant relative of corn with a differentgametic chromosome number (n=18), and varying ploidy levels ranging from2n=36 to 2n=108. Other species of gamagrass, namely T. dactyloides andT. floridanum, have been crossed with corn and hybrids are male sterileand essentially female sterile. Attempts to cross Tripsacum and annualteosinte, the closest relative of corn that most scientists believe isits wild progenitor, failed. Many plant breeders believe that gamagrasshas significant potential for improving corn by expanding its geneticdiversity.

In 1985, crosses were made by pollinating diploperennis with pollen fromEastern gamagrass, T. dactyloides. U.S. Plant Pat. No. 6,906 for ‘SunDance’, the hybrid from that cross, was issued Jul. 4, 1989. In April,1985, the reciprocal cross to tetraploid Tripsacum was made using Z.diploperennis as pollen donor and T. dactyloides as pollen recipient,and U.S. Plant Pat. No. 7,977 for ‘Tripsacorn’, the hybrid from thatcross, was issued Sep. 15, 1992. In January, 1988, Z. diploperennis waspollinated with pollen from a diploid (2n=36) T. dactyloides. U.S. PlantPat. No. for ‘Sun Star’, the hybrid from that cross, was issued Sep. 3,1996.

On Jan. 26, 2002, Z. diploperennis was pollinated with pollen fromTripsacum laxum. The seed, planted May 27, 2002, germinated and grewinto a normal, fully fertile plant that is perennial and produces viablefruits year-round in the greenhouse. The plant has been propagated byrhizome divisions, cuttings, and anther culture. Various corn linescrossed with ‘Venus Express’ have produced fertile corn plants. Thisdiploperennis-Tripsacum recombinant, like the recombinants ‘Sun Dance’,‘Tripsacorn’, and ‘Sun Star’, provides a genetic bridge for moving genesfrom Tripsacum into corn using conventional plant breeding methods, andthereby establishing a link between these wild grasses and modern cornthat may be beneficial in corn improvement breeding programs. Uniquepropagation of this plant through successive generations by means ofrhizome divisions, cuttings, and anther culture have demonstrated thatthe new plant has not only retained the continuous and abundantproduction capability, but also that its distinguishing characteristicshold true from generation to generation and appear to be firmly fixed.Examination of the roots revealed that Venus Express has well developedair passages referred to as aerenchyma. This property provides rootsoxygen so they can tolerate flooded soils. It also allows the roots togrow deep below the hardpan, a characteristic that conveys good droughttolerance along with acid soil and aluminum tolerance, and gives theplant potential for use in bioremediation. Propagation has taken placein Durham, N.C. All activities including making the cross pollinationbetween the two genera, growing the respective recombinant plant from aseed, and further reproducing the plant asexually from rhizomes, stemcuttings, and anther culture, took place in a greenhouse in Durham, N.C.

DESCRIPTION OF ILLUSTRATIONS

This new corn plant is illustrated by the accompanying full colorphotographs that include:

FIG. 1, a fully grown plant showing the characteristic habit of manyculms growing from the base;

FIG. 2, a closeup of culms enwrapped by the red sheath;

FIG. 3, a closeup of the ciliate leaf margins;

FIG. 4, a rhizome;

FIG. 5, a distichously arranged pistillate spike with red styles, and

FIG. 6, mature seeds;

FIG. 7, rooted cuttings;

FIG. 8, a tassel branch showing a plantlet growing out of an anther, and

FIG. 9, a tassel with multiple plantlets growing out of anthers.

-   The plant:-   Origin: Seedling.-   Parentage:    -   -   Seed parent.—Zea diploperennis (2n=20). Provenance: Upper            Las Joyas, Sierra de Manantlan, Jalisco, Mexico, Iltis, Nee            & Guzman Acc. #1250, Jan. 1979.        -   Pollen parent.—Tripsacum laxum (2n=72 Provenance: CEL 4873,            Veracruz, Mexico, H. T. Stalker, Nov. 1974.-   Chromosome number: 2n=20.-   Habit: Essentially erect; as many as 60 primary culms, usual number    about 50.-   Duration:    -   -   Perennial.—Sends out shoot from rhizomes.-   Culm:    -   -   Height.—Up to 2.2 meters: slender, simple with occasional            branching from the nodes of the culm; glabrous; round to            slightly oval in cross section; Diameter 4.5 mm×7.5 mm.            Color: light green (Pantone 14-0627 TP “Shadow Green”).        -   Nodes.—glabrous; internode length 8.5 cm.        -   Sheath.—enwraps the culm, margins not united; margins            ciliate; Color: deep red (Pantone #19-1726 TP “Cordovan”) to            light red (Pantone #18-1635 TP “State Rose”).        -   Ligule.—present on adaxial side of leaf at junction of blade            and sheath; length: 3.6 mm; membranaceous, irregular edge,            Color: light green (Pantone #14-0627 TP “Shadow Green”).-   Leaf blade: alternate; distichous; sheathing base; parallel veined;    narrowly linear, flat, thin.    -   -   Length.—26.0 cm. Width: 3.1 cm. Color: green (Pantone            #18-0324 TP “Calliste Green).        -   Leaf tip.—attenuate.        -   Entire margin.—ciliate, Color: red (Pantone #19-1629 TP            “Ruby Wine”).        -   Midrib.—Color: white (Pantone #11-0601 TP “Bright White”).        -   Adaxial surface.—hirsute.        -   Abaxial surface.—Glabrous.        -   Prominent parallel veins.—5 per 1.0 cm width.-   Rhizome: underground stem that produces buds at the nodes from which    new plants emerge.    -   -   Internode.—Round. Length: 2.5 cm. Diameter: 1.0 cm. Color:            light beige (Pantone 13-1107TP “Whisper pink”).-   Inflorescence:-   Blooming period: Continuous year-round in the greenhouse.-   Monoecious: Separate male and female flowers on same plant.-   Staminate flowers: May be of two types: one inflorescence type borne    as paired spikes on a slender rachis forming a branched terminal    spike, generally composed of two branches. Alternatively, staminate    spikelets may be borne on a single spike at the summit of a culm or    on the same spike and above the pistillate flowers. Axis. — Stiff,    continuous, ascending.    -   -   Spikelet.—Two-flowered, one sessile, one pedicellate;            laterally compressed awnless;        -   Length.—8.6 mm. Width: 3.2 mm. In pairs on one side of a            persistent central axis.        -   Pedicel length.—3.9 mm.        -   Glumes.—Outer glume: cartilaginous, tapering to an acute            tip, ciliate, flat, several nerved, margins scabrous. Inner            glume: chartaceous.-   Pollen viability: 84%.-   Pistillate flowers: Borne in leaf axils; three or more pistillate    spikelets per node, one sessile and others pedicellate; pedicel    length: up to 27 cm; spikelets distichously arranged; pistillate    flower consists of a single rowed spike of 4 to 7 trapezoidal    caryopses in hard, shell-like fruitcases; may be enclosed in a    single leaf sheath or not enclosed; caryopses disarticulate upon    maturity.    -   -   Styles.—pilose. Length: 8.75 cm.        -   Color.—Ranges from pastel parchment (Pantone #11-0603) to            deep red when fully emerged (Pantone #19-1726 TP “Cordova”).        -   Length.—9.0 cm.-   Fruit: As many as 11 ears per culm per blooming period; flowers    produced year-round.-   Maturity: 45 days following fertilization.-   Kernel (Dried): Angular caryopses in hard, shell-like fruitcases,    disarticulate upon maturity:-   Size: Length: 7.5 mm, Width: 4.5 mm, Thickness: 4.0 mm.-   Shape: Trapezoidal.-   Color: Ranges from dark brown (Pantone #181124 TP “Partridge”) to    light brown (Pantone #16-1320TP “Nougat”) with dark brown speckles    to beige (Pantone #13-1106TP “Pearl Gray”) with brown speckles.-   Weight: 20 seed (unsized samples): 1.5 gm.-   Comparative parental characteristics:    -   -   Duration.—Zea diploperennis perennial sends out shoots from            underground bulbils. Tripsacum laxum perennial from            rhizomes.        -   Culm.—Zea diploperennis Culm round in cross section;            Diameter: 2.5 cm; sheath tightly closed completely            enwrapping the culm; Color: red (Pantone #19-1530 TP “Burnt            Russet”), Internode length: 17.5 cm. T. laxum Culm oval in            cross section; Diameter: 0.4 cm×1.5 cm; sheath splits apart            and partially enwraps the culm, Color: red (Pantone #19-1726            TP “Cordova”), Internode length: 28.3 cm.        -   Leaf blade.—Z. diploperennis. Length: 77.5 cm. Width 5.0 cm;            margins pink serrulate from midsection of blade to tip;            adaxial surface: hirsutullous; prominent veins: 6 per 1.0 cm            width, Color: green (Pantone #18-0324 TP “Calliste            Green). T. laxum. Length: 75.0 cm. Width: 5.0 cm; margins            scabrous; adaxial surface: glabrous; veins: 5 per 1.0 cm            width.        -   Blooming period.—Z. diploperennis twice a year, end of March            and end of September for about a month. T. laxum from            January to March.        -   Staminate flowers.—Z. diploperennis borne in tassel with 6            to 7 branches at summit of culm. Total length staminate            spike: 33.8 cm. Staminate spikelet pedicel length: 3 mm.            Staminate spikelet outer glume length: 12.5 mm. T. laxum            staminate flowers borne above pistillate flowers on a spike            borne in a branching, pendulous terminal inflorescence with            five to twenty branches; Total length staminate spike:            29.4 cm. Staminate spikelet pedicel length: 2.6 mm.            Staminate spikelet outer glume length: 6.4 mm.        -   Pistillate flowers.—Z. diploperennis caryopsis triangular in            hard bony fruitcases; Length: 8 mm; Width: 4.5 mm; Color:            black (Pantone #10-0303), dark brown (Pantone #10-1020) or            brown speckled. T. laxum caryopsis in hard, rectangular            fruitcases; Length: 7.0 mm; Width: 3.2 mm. Color: brown            (Pantone #18-1033TP “Dachshund”) Style length: 2.9 mm,            Color: red (Pantone #19-1726 TP “Cordova”).        -   Color reference: The Pantone Textile Color Guide. 1992.            Pantone, Inc., Carlstadt, N.J. ISBN 1-881509-32-X.

COMPARISON TO ‘SUN DANCE’, ‘TRIPSACORN’ AND ‘SUN STAR’

Although this plant is similar to ‘Sun Dance’, ‘Tripsacorn’, and ‘SunStar’, it is distinctive from these plants because it was derived fromcrossing Z. diploperennis with T. laxum (2n=72), section Fasciculata;whereas ‘Sun Dance’ and ‘Tripsacom’ hybrids were derived from crossingZ. diploperennis with a tetraploid T. dactyloides (2n=72), sectionTripsacum, and ‘Sun Star’ was derived from crossing Z. diploperenniswith a diploid T. dactyloides (2n−36), section Tripsacum. In contrast tothe sessile pair of staminate flowers characteristic of T. dactyloidesand section Tripsacum in general, T. laxum has one sessile and onepedicillate staminate member of the pair of staminate flowers, which ischaracteristics of the Tripsacum members of section Fasciculata. VenusExpress is distinguished from the three diploperennis-T. dactyloidesrecombinants by its smaller leaves, more numerous culms, and year-roundflowering. T. laxum and diploperennis are used as forage plants. Thegreater number of culms and year-round flowering of Venus Express aretraits not characteristic of either parent that give it added value as aforage crop in addition to its capacity to serve as a genetic bridge tomove T. laxum genes into corn.

1. A new and distinct variety of corn plant, substantially as hereinshown and described, that is characterized by its profuse production offruit, perennial habit, vigorous vegetative production of culms, rootswith aerenchyma, asexual reproduction by rhizomes, stem cuttings, andanther culture, and its good combining ability with corn that permitsmovement of new genes and agronomic traits into corn using conventionalplant breeding methods.